Academic literature on the topic 'Lower radical construction'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Lower radical construction.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Lower radical construction"
1
McDougall, Robert. "A generalisation of the lower radical class." Bulletin of the Australian Mathematical Society 59, no. 1 (February 1999): 139–46. http://dx.doi.org/10.1017/s000497270003269x.
Full textAbstract:
In this work we demonstrate that the lower radical class construction on a homomorphically closed class of associative rings generates a radical class for any class of associative rings. We also give a new description of the upper radical class using the construction on an appropriate generating class.
2
Sands, A. D. "On the lower radical construction of Tangeman and Kreiling." Proceedings of the Edinburgh Mathematical Society 33, no. 2 (June 1990): 203–5. http://dx.doi.org/10.1017/s0013091500018137.
Full text
3
Zhang, Zhirang, and Xuemei Li. "The Upper Radical Property and Lower Radical Property of Groups." Algebra Colloquium 18, no. 04 (December 2011): 693–700. http://dx.doi.org/10.1142/s100538671100054x.
Full textAbstract:
We take in this paper an arbitrary class [Formula: see text] of groups as a base, and define a radical property 𝒫 for which every group in [Formula: see text] is 𝒫-semisimple. This is called the upper radical property determined by the class [Formula: see text]. At the same time, we define a radical property 𝒫 for which every group in [Formula: see text] is a 𝒫-radical group. This is called the first lower radical property determined by the class [Formula: see text]. Also, we give another construction leading to the second lower radical property which is proved to be identical with the first one.
4
Vigus, Meagan. "Antipassive constructions: Correlations of form and function across languages." Linguistic Typology 22, no. 3 (October 25, 2018): 339–84. http://dx.doi.org/10.1515/lingty-2018-0013.
Full textAbstract:
Abstract This paper presents a cross-linguistic investigation of the antipassive within the framework of Radical Construction Grammar. Based on function, this study identifies constructions in 70 languages from 25 language families and four geographical macro areas. Iconically motivated correlations were found between functions and the morphosyntactic strategies they employ. The results of this study suggest that constructions indicating the lower individuation of patients and constructions indicating the lower affectedness of patients, previously grouped together as ‘antipassive’, should be considered two separate construction types. This is based on their separate functions, the distinct morphosyntactic strategies used to encode them across languages, and differences in productivity with regard to semantic classes of verbs.
5
Veldsman, Stefan. "Sufficient conditions for a well-behaved Kurosh-Amitsur radical theory." Proceedings of the Edinburgh Mathematical Society 32, no. 3 (October 1989): 377–94. http://dx.doi.org/10.1017/s0013091500004648.
Full textAbstract:
Kurosh-Amitsur radical theories have been developed for various algebraic structures. Whenever the notion of a normal substructure is not transitive, this causes quite some problems in obtaining satisfactory general results. Some of the more important questions concerning the general theory of radicals are whether semisimple classes are hereditary, do radical classes satisfy the ADS-property, can semisimple classes be characterized by closure conditions (e.g., is semisimple=coradical), is Sands' Theorem valid and lastly, does the lower radical construction terminate. For associative and alternative rings, all these questions have positive answers. The method of proof is the same in both cases. In [15], Puczylowski used the results of Terlikowska-Oslowska [18, 19] and hinted at a condition which is crucial in obtaining the positive answers to the above questions.
6
Fang, Honghin, and Patrick Stewart. "Radical Theory for Granded Rings." Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics 52, no. 2 (April 1992): 143–53. http://dx.doi.org/10.1017/s1446788700034315.
Full textAbstract:
AbstractIn this paper we propose a general setting in which to study the radical theory of group graded rings. If is a radical class of associative rings we consider two associated radical classes of graded rings which are denoted by G and ref. We show that if is special (respectively, normal), then both G and ref are graded special (respectively, graded normal). Also, we discuss a graded version of the ADS theorem and the termination of the Kurosh lower graded radical construction.
7
ANDRUSZKIEWICZ, R. R., and M. SOBOLEWSKA. "ON THE STABILISATION OF ONE-SIDED KUROSH’S CHAINS." Bulletin of the Australian Mathematical Society 86, no. 3 (February 23, 2012): 473–80. http://dx.doi.org/10.1017/s0004972712000068.
Full text
8
Andruszkiewicz, R. R. "On accessible subrings of associative rings." Proceedings of the Edinburgh Mathematical Society 35, no. 1 (February 1992): 101–7. http://dx.doi.org/10.1017/s0013091500005356.
Full textAbstract:
We describe for every natural n the class of rings R such that if R is an accessible (left accessible) subring of a ring then R is an n-accessible (n-left-accessible) subring of the ring. This is connected with the problem of the termination of Kurosh's construction of the lower (lower strong) radical. The result for n = 2 was obtained by Sands in a connection with some other questions.
9
Sun, Hong Yao, Zheng Yang, Gao Xia Sun, and Xue Feng Xu. "The Research of Silane Oligomer with Lower Valatilization Rate for Protecting Concrete." Applied Mechanics and Materials 357-360 (August 2013): 1318–22. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.1318.
Full textAbstract:
As one of the measures to improve the durability of concrete, silane penetrating hydrophobic agents can preserve the properties of respiratory function of concrete and can prevent the penetration from harmful medium such as chloride ions. Because of low molecular weight of the silane penetrating hydrophobic agent such as isobutyl triethoxysilane, high volatilization rate of silane can result in waste of material in construction process. The silane oligomer was obtained by radical polymerization reaction with suitable monomers, initiators and reaction conditions. Furthermore, we verified the structure of the silane oligomer by FT-IR spectroscopy and got its molecular weight by GPC(Gel Permeation Chromatography). The silane oligomer with lower volatilization rate has excellent properties of hydrophobicity, higher penetration depth and resistance to chloride ions penetration.
10
Lobera, Josep. "Migrants and 'Patria'. The imagined community of the radical left in Spain." Teknokultura. Revista de Cultura Digital y Movimientos Sociales 17, no. 1 (January 29, 2020): 59–68. http://dx.doi.org/10.5209/tekn.66912.
Full textAbstract:
The emergence of inclusive populist parties disputes the social construction of the ‘people’ to the exclusive populism, recently generating new academic debates. Do the new radical left parties have a nationalist character? Are populism and nationalism two inseparable dimensions? Drawing on an original dataset in Spain, this article shows that Podemos’ supporters are significantly less nationalist, expressing more open attitudes towards cultural diversity and immigration, and lower levels of Spanishness than voters from other parties. Arguably, Podemos operates as an antagonistic political option to the traditional positions of the populist radical right (PRR), building an inclusive imagined community around a type of constitutional patriotism or republican populism. These findings contribute to the scholar debate on the relationship of nationalism and populism, bringing to discussion the core values of the supporters of a populist party as a complementary element to its categorization.
Dissertations / Theses on the topic "Lower radical construction"
1
(9788648), Guy Cooke. "On lower radical type constructions." Thesis, 2010. https://figshare.com/articles/thesis/On_lower_radical_type_constructions/13456742.
Full textAbstract:
This research is essentially an investigation into lower radical type construction and the consequences thereof. Dealing primarily in associative rings, the aim of this thesis is to construct - and investigate - a generalised lower radical type construction that encapsulates McDougall's base radical class construction and Stewart's strict radical class construction. Beginning with some preliminary results and a brief account of the lower radical (type) constructions in associative rings, we develop the basic concepts and notations used throughout the investigation. After determining a number of substructures suitable for use in our lower radical type construction (a ϱ-radical class), we go on to examine some of the similarities, differences and properties of the ϱ-radical class relative to those of the existing contructions.
In the lattice of all radical classes, we focus on the connections that both the base and strict radical constuctions have respectively to two specific ϱ-radical constructions. Moreover, we determine that all such ϱ-radicals are contained in particular non-trivial radical classes, and subsequently position these against the so called concrete radicals in the lattice of all radical classes. We also demonstrate that the structure of a lattice of ϱ-radical classes is partially dependent on the generating class, and thus not fixed in terms of construction.
In considering the dual construction to the ϱ-radical class, we learn that unlike the ϱ-radical construction always generating a radical class, the dual construction need not always generate a semisimple class. We consider some of the cases in which the dual is semisimple, and give a sufficient condition to determine the ϱ-properties that so generate a ϱ-semisimple class. Whilst on the subject of semisimple classes, we generalise the notion of the strongly R-semisimple ring, and explore when a class of such rings is a radical class.
The thesis concludes by generalising the ϱ-radical construction to suit an arbitrary GS-category. In doing so we validate the ϱ-radical construction in structures such as groups, near-rings, nonassociative rings, any variety of rings or algebras, (Hausdorff) topological groups and rings, and vector value spaces to name just a few. This has certainly opened a door for further investigation, in these and possibly other branches of mathematics.
The simplicity and flexibility of the theory developed in this research provides an accessibility that may have wider applications in algebra -- Abstract.
Books on the topic "Lower radical construction"
1
Duffley, Patrick. Linguistic Meaning Meets Linguistic Form. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198850700.001.0001.
Full textAbstract:
This book steers a middle course between two opposing conceptions that currently dominate the field of semantics, the logical and cognitive approaches. It brings to light the inadequacies of both frameworks, and argues along with the Columbia School that linguistic semantics must be grounded on the linguistic sign itself and the meaning it conveys across the full range of its uses. The book offers 12 case studies demonstrating the explanatory power of a sign-based semantics, dealing with topics such as complementation with aspectual and causative verbs, control and raising, wh- words, full-verb inversion, and existential-there constructions. It calls for a radical revision of the semantics/pragmatics interface, proposing that the dividing-line be drawn between semiologically-signified notional content (i.e. what is linguistically encoded) and non-semiologically-signified notional content (i.e. what is not encoded but still communicated). This highlights a dimension of embodiment that concerns the basic design architecture of human language itself: the ineludable fact that the fundamental relation on which language is based is the association between a mind-engendered meaning and a bodily produced sign. It is argued that linguistic analysis often disregards this fact and treats meaning on the level of the sentence or the construction, rather than on that of the lower-level linguistic items where the linguistic sign is stored in a stable, permanent, and direct relation with its meaning outside of any particular context. Building linguistic analysis up from the ground level provides it with a more solid foundation and increases its explanatory power.
2
Spencer, Jane. Writing About Animals in the Age of Revolution. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198857518.001.0001.
Full textAbstract:
This book argues that shifting attitudes to nonhuman animals in eighteenth-century Britain affected the emergence of radical political claims based on the concept of universal human rights. It examines a tension in 1790s radicalism between the anthropocentrism of the concept of the ‘rights of man’, and the challenge to human exceptionalism entailed by attempts to extend benevolent consideration to nonhuman animals. The development of a naturalistic and sympathetic literature of animal subjectivity is traced with particular attention to the innovatory representation of nonhuman animal perspectives within children’s literature. The study explores the complex relationship between animal representation and claims for human rights through an investigation of writing by and about four overlapping human groups—children, women, slaves, and the lower classes—whose social subordination was grounded in their cultural construction as less than fully human. Emancipatory movements of political reform, abolition, and feminism, and the animal representations produced within those movements, were affected by the varying forms of animalization applied to each oppressed group. A final chapter considers the legacy of 1790s animal rights discourses in the early-nineteenth-century campaign for anti-cruelty legislation. The book’s many literary animals include the ass, ambiguous emblem of sympathetic animal writing; the great ape or ‘orang-outang’, central to racist discourse; and the pig, adopted by 1790s radicals to signify their rebellion. Writers considered include Sterne, Coleridge, Southey, Wordsworth, Clare, Wollstonecraft, Barbauld, Hays, Mary Robinson, Equiano, Sancho, Cugoano, Clarkson, Thomas Spence, Daniel Isaac Eaton, John Oswald, Joseph Ritson, Thomas Erskine, and John Lawrence.
Book chapters on the topic "Lower radical construction"
1
Graf, William L. "Sediment and Plutonium Storage Downstream from Cochiti." In Plutonium and the Rio Grande. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195089332.003.0015.
Full textAbstract:
Downstream from White Rock Canyon and the reaches discussed in Chapter 9, the Rio Grande takes on a different character because of the presence of Cochiti Dam at the lower end of the canyon. From that point downstream, the river’s present appearance and behavior reflect the influence of the dam, which was closed in 1973. Although the channel has become narrower throughout the length of the Rio Grande since the 1930s, this change is most pronounced south of Cochiti Dam. Downstream from the Los Lunas representative reach (which ends near Bernardo), the character of the Rio Grande changes radically. Immediately below Bernardo, the Rio Puerco joins the main river, bringing with it a huge load of sediment. The Rio Grande Valley becomes much wider below Bernardo, and the twentieth-century narrowing of the channel, aided by engineering works, is even more pronounced than in upstream areas, and the vegetation community is dominated by tamarisk. The final three representative reaches discussed in this chapter share the features of great valley width, extensive channel changes, and widespread impacts of engineering works. The Peña Blanca reach, a 5-km channel section, represents conditions common along 40 km of the Northern Rio Grande between Cochiti Pueblo (site of Cochiti Dam) and the confluence with the Jemez River. The river passes Peña Blanca, a settlement based on irrigated agriculture dating from the early nineteenth century. The reach is typical of the conditions in a portion of the river where the flood plain is several times the width of the channel and where the channel has been exceedingly unstable. The reach is also instructive concerning the results of levee construction (in 1953) and dam closure (in 1973). The behavior of the channel in the Pena Blanca reach between the early 1940s and about 1990 has consistently included locational instability and progressive adjustment from a broad-braided configuration to a narrow, straighter alignment. In the 1940s, the channel was wide and unstable, with numerous major and minor threads, but the gradual reduction in water yield and radical reduction in the annual flood peaks resulted in the progressive isolation and closure of secondary channels.
2
Taber, Douglass F. "The Trost Synthesis of (-)-Pseudolaric Acid B." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0085.
Full textAbstract:
(-)-Pseudolaric acid B 3, isolated from the bark of the golden larch Pseudolarix kaempferi, shows potent antifungal activity. A key step in the total synthesis of 3 described (J. Am. Chem. Soc. 2008 , 130 , 16424) by Barry M. Trost of Stanford University was the free radical cyclization of 1 that established the angular ester and the trans ring fusion of 2 and thus of 3. To prepare the bicyclic skeleton of 1, the authors envisioned the Rh-mediated intramolecular addition of the alkyne of 11 to the alkenyl cyclopropane. The acyclic centers of 11 were established by Noyori hydrogenation of (equilibrating) racemic 4. One enantiomer reduced much more quickly than the other, leading to 5. The absolute configuration of the cyclopropane was set by Charette cyclopropanation of the monosilyl ether of the inexpensive diol 8. The two components were then coupled using a Corey-Schlosser protocol. Alkylation of the ylide 10 with 7 gave a new phosphonium salt, which in situ was deprotonated and condensed with the aldehyde 9 . The resulting betaine was deprotonated and quenched, then exposed again to base to give the trans alkene 11. It is important in this procedure to use PhLi as the base, because the alkyl lithium can displace the alkyl group on phosphorus. The product from Ru-catalyzed cyclization was the expected 1,4-diene 12 . Fortunately, it was found that TBAF desilylation led to concomitant alkene migration, to give the more stable conjugated diene 13. Selective epoxidation of the more electron-rich alkene fol lowed by exposure to strong base then delivered 14 , with the requisite angular oxygenation established. Pseudolaric acid B 3 would be derived from cyclization of the selenocarbonate of a tertiary alcohol. In fact, however, attempted cyclization of such selenocarbonates led only to decarboxyation and reduction. Even with the selenocarbonate 1 prepared from the secondary alcohol, the cyclization to 2 required careful optimization, including using not AIBN but azobis(dicyclohexylcarbonitrile) as the radical initiator. Acetylide addition to the ketone 15 could be effected with high diastereocontrol, but lactone construction proved elusive. Alkaline conditions led quickly to addition of the angular hydroxyl to the activated alkene in the seven-membered ring.
3
Chowdhury, Fariah. "Permanently Temporary." In Discourse Analysis as a Tool for Understanding Gender Identity, Representation, and Equality, 175–203. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0225-8.ch009.
Full textAbstract:
Canada's immigration policy radically shifted under Stephen Harper's federal Conservative Party government, which ruled from 2006 to 2015. The Temporary Foreign Worker Program (TFWP) is one key example of how migrants are increasingly entering Canada through a racially structured hierarchy of citizenship that privileges whiteness, while increasing the precarity of racialized migrants as they live, work, and contribute to the Canadian economy. This chapter offers a detailed policy analysis of Canada's TFWP, focusing on how the program marginalizes migrant workers as “un-Canadian” by placing them in racial, gender, and class hierarchies of belonging. This paper will discuss and outline recent changes and developments in Canada's TFWP, specifically those related to migrants classified as ‘lower-skilled' workers. While some labour needs in Canada can be read as truly temporary (for example, where workers were required to construct venues for the 2010 Vancouver Winter Olympic Games or other short-term construction projects), the lack of accountability within the TFWP in Canada has led to some occupations being misleadingly framed as ‘temporary', thereby creating a class of migrant workers who are “permanently temporary.” I will argue that the labeling of racialized migrants as “temporary workers” offers employers a structural incentive to keep wages systematically low and maintain poor working conditions, all couched under a guise of “competitiveness.” In this light, “temporary” work becomes synonymous with low-wage exploitation, and continues to strengthen a historic racist nation-state project in Canada. Further, this paper will argue that giving temporary status to migrant workers, rather than permanent residency, serves to limit access to social rights and services, only deepening their levels of exploitation. Finally, I argue that recent increases in TFWs is a symptom of a global trend towards the neoliberalization of citizenship, which has seen the unethical individualization of rights and the privatization of services across many fields.
4
Chowdhury, Fariah. "Permanently Temporary." In Immigration and the Current Social, Political, and Economic Climate, 142–63. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-6918-3.ch008.
Full textAbstract:
Canada's immigration policy radically shifted under Stephen Harper's federal Conservative Party government, which ruled from 2006 to 2015. The Temporary Foreign Worker Program (TFWP) is one key example of how migrants are increasingly entering Canada through a racially structured hierarchy of citizenship that privileges whiteness, while increasing the precarity of racialized migrants as they live, work, and contribute to the Canadian economy. This chapter offers a detailed policy analysis of Canada's TFWP, focusing on how the program marginalizes migrant workers as “un-Canadian” by placing them in racial, gender, and class hierarchies of belonging. This paper will discuss and outline recent changes and developments in Canada's TFWP, specifically those related to migrants classified as ‘lower-skilled' workers. While some labour needs in Canada can be read as truly temporary (for example, where workers were required to construct venues for the 2010 Vancouver Winter Olympic Games or other short-term construction projects), the lack of accountability within the TFWP in Canada has led to some occupations being misleadingly framed as ‘temporary', thereby creating a class of migrant workers who are “permanently temporary.” I will argue that the labeling of racialized migrants as “temporary workers” offers employers a structural incentive to keep wages systematically low and maintain poor working conditions, all couched under a guise of “competitiveness.” In this light, “temporary” work becomes synonymous with low-wage exploitation, and continues to strengthen a historic racist nation-state project in Canada. Further, this paper will argue that giving temporary status to migrant workers, rather than permanent residency, serves to limit access to social rights and services, only deepening their levels of exploitation. Finally, I argue that recent increases in TFWs is a symptom of a global trend towards the neoliberalization of citizenship, which has seen the unethical individualization of rights and the privatization of services across many fields.
Conference papers on the topic "Lower radical construction"
1
Amirjani, Rahmatollah. "Labour Housing and the Normalisation of Modernity in 1970s Iran." In The 38th Annual Conference of the Society of Architectural Historians Australia and New Zealand. online: SAHANZ, 2022. http://dx.doi.org/10.55939/a4020p1tmw.
Full textAbstract:
In the 1970s, rapid modernisation fuelled population displacement and increased the number of workers in the large cities of Iran, in particular Tehran. In response, the Imperial Government initiated several housing programs focusing on the provision of megastructures on a large scale. Consequently, a new opposition formed among some sectors of society, regarding the dissemination of gigantic buildings in the International or Brutalist styles. Critics and clerics argued that the radical government interventions not only polarised the image of Islamic identity in cities, but also affected the behaviour of people towards, and their opinions concerning, the Islamic lifestyle. Additionally, some claimed the state aimed to normalise its project of modernity and rapid westernisation for the mid- and lower classes using housing. In this regard, this article investigates the 1970s imperial government social housing programs to verify these claims. Using an extensive literature review, documentary research, observation, and descriptive data analysis, this article argues that, despite the government politics and modernisation tendencies in the 1970s, consumerism, political competition, the state of Cold War, and the emergence of new construction techniques, all resulted in the emergence of mass-produced megastructures offering a new luxurious lifestyle to residents. While the life and hygiene of the different classes were improved, these instant products inevitably facilitated the normalisation of Western lifestyle among the mid- and low-income groups of the society. Eventually, this visible social transition was utilised by opposition leaders as another excuse to topple the Pahlavi regime under the 1979 Islamic Revolution.
2
Faravelli, Tiziano, Alessio Frassoldati, Eliseo Ranzi, Francesco Miccio, and Michele Miccio. "Modeling Homogeneous Combustion in Bubbling Beds Burning Liquid Fuels." In 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-133.
Full textAbstract:
This paper presents a first implementation of a model for the description of homogeneous combustion of different fuels in fluidized bed combustors (FBC) at temperatures lower than the classical value for solid fuels, i.e. 850°C. Model construction is based on a key feature of the bubbling fluidized bed: a fuel-rich (endogenous) bubble is generated at the fuel injection point, travels inside the bed at constant pressure and undergoes chemical conversion in presence of mass transfer with the emulsion phase and of coalescence with air (exogenous) bubbles formed at the distributor and, possibly, with other endogenous bubbles. The model couples a fluid-dynamic sub-model based on the two phases theory of fluidization with a sub-model of gas phase oxidation. To this end, model development takes full advantage of a detailed chemical kinetics scheme, which includes both the low and high temperature mechanisms of hydrocarbon oxidation and accounts for about 200 molecular and radical species involved in more than 5000 reactions. Simple hypotheses are made to set-up and close mass balances of the various species as well as enthalpy balances in the bed. First, conversion and oxidation of gaseous fuels (e.g. methane) have been calculated as a test case for the model; then, n-dodecane has been taken into consideration to simply represent a diesel fuel by means of a pure hydrocarbon. Model predictions qualitatively agree with some evidences coming from experimental data reported in the literature. The fate of hydrocarbon species is extremely sensitive to temperature changes and oxygen availability in the rising bubble. A preliminary model validation has been attempted against the results of experiments carried out on a pre-pilot, bubbling combustor fired with underbed injection of a diesel fuel. In particular, model results confirm the trends that the heat release either in the bed or in the freeboard experimentally shows as a function of bed temperature. At lower emulsion phase temperatures many combustible species leave unburned the bed, post-combustion occurs past the bed and freeboard temperature considerably increases; as it is well known, this is an undesirable feature from the viewpoints of practical application and emission control.
3
Cai, Xiaoyu, Suizheng Qiu, Guanghui Su, and Changyou Zhao. "Steady-State Thermal-Hydraulic Analysis of a Particle-Bedded Boiling Water Reactor." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75050.
Full textAbstract:
The current Light Water Reactors both BWR and PWR have extensive nuclear reactor safety systems, which provide safe and economical operation of Nuclear Power Plants. During about forty years of operation history the safety systems of Nuclear Power Plants have been upgraded in an evolutionary manner. The cost of safety systems, including large containments, is really high due to a capital cost and a long construction period. These conditions together with a low efficiency of steam cycle for LWR create problems to build new power plants in the USA and in the Europe. An advanced Boiling Water Reactor concept with micro-fuel elements (MFE) and superheated steam promises a radical enhancement of safety and improvement of economy of Nuclear Power Plants. In this paper, a new type of nuclear reactor is presented that consists of a steel-walled tube filled with millions of TRISO-coated fuel particles (Micro-Fuel Elements, MFE) directly cooled by a light-water coolant-moderator. Water is used as coolant that flows from bottom to top through the tube, thereby fluidizing the particle bed, and the moderator water flows in the reverse direction out of the tube. The fuel consists of spheres of about 2.5 mm diameter of UO2 with several coatings of different carbonaceous materials. The external coating of steam cycle the particles is silicon carbide (SiC), manufactured with chemical vapor deposit (CVD) technology. Steady-State Thermal-Hydraulic Analysis aims at providing heat transport capability which can match with the heat generated by the core, so as to provide a set of thermal hydraulic parameters of the primary loop. So the temperature distribution and the pressure losses along the direction of flow are calculated for equilibrium core in this paper. The calculation not only includes the liquid region, but the two phase region and the superheated steam region. The temperature distribution includes both the temperature parameters of micro-fuel elements and the coolant. The results show that the maximum fuel temperature is much lower than the limitation and the flow distribution can meet the cooling requirement in the reactor core.
4
Young, Raymond, and Manou Kashani. "Carbon Footprint Minimization for Deepwater Pipelay Construction." In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31105-ms.
Full textAbstract:
Abstract With recent oil and gas discoveries in deepwater offshore, these regions have become the hotspots for oil and gas exploration. It is for this reason that major pipelay contractors are developing more advanced construction vessels with high lay tension capacity, payload and high specification dynamic positioning (DP) systems to operate at even deeper water depths. It is shown that at water depths of greater than 1000 m, one of the major construction costs is fuel consumption, which is directly related to the level of thrust and hold back tension the laybarge is required to maintain during pipelay operations. Furthermore, the fuel consumption and the resulting carbon footprint, is shown to increase disproportionally as the laybarge thrust increases at deeper water depths. For example, a deepwater laybarge (DP3 class) with a typical operating power of 40MWe can consume 130 metric tonnes of diesel fuel per day (1.5 kg/s) with carbon dioxide equivalent emissions (CO2e) of 3,200 kg per tonne of fuel. This is a substantial measure of emissions, typical of a pipelay vessel during pipe lay operations. It is for this reason that American and European air pollutant emission inventory guidelines expect environmental impact documents for all marine activities, including construction, to be calculated and submitted to relevant environmental protection agencies. By comparison, a typical car will produce around 4,600 kg of CO2e per year. Currently, deepwater pipeline engineering and design is based on relevant offshore design codes and standards, e.g. DNV-GL and API. Within the framework of those codes and standards, a design approach is presented within this paper that shows that, by properly combining pipe strength and stiffness characteristics with pipelay construction loads, a unique bending strain limit can be defined that would lead to the most economical solution that minimizes the vessel thrust and thereby radically reduce fuel consumption and associated CO2e emissions during pipelay activities. This unique design approach would be of interest to operators, pipe manufacturers as well as the pipelay contractors. Because of the construction economy and the minimizing of the carbon footprint, this approach is an attractive design method to all concerned parties, including environmental protection agencies. Since the design approach promotes higher steel grades, it would be very much in the interest of pipe mills to further develop and elevate the use of higher steel grades higher than the present widely used API 5L, X-65. Pipelay contractors will benefit by installing pipe with lower levels of thruster power, resulting in safer and a more reliable station keeping and, most significantly, a lower fuel consumption.
5
Mandahus, Pia, Lukas Eberhardsteiner, Bernhard Pichler, Mehdi Aminbaghai, and Ronald Blab. "Validation Of A New Method For Determining The Remaining Service Life Of Rigid Pavements." In 12th International Conference on Concrete Pavements. International Society for Concrete Pavements, 2021. http://dx.doi.org/10.33593/2km27z9r.
Full textAbstract:
About a half of the Austrian highways are rigid pavement constructions, and increasingly more money has to be invested in their renovation and redevelopment. However, there are different approaches for the evaluation of the condition assessment of concrete pavements. The aim of the research presented in this paper is a concept for assessing the condition of a road section in rigid pavement. This consists of a structural and a visual assessment scheme for selecting appropriate maintenance actions. For the verification of this new method of assessment of the structural condition of concrete pavements, several field tests were examined. Furthermore, a case study was carried out to examine the level of influence of several input parameter. This analysis shows that the influence of the layer thickness is very high, while the influence of the modulus of elasticity of the existing concrete is significant lower. The FWD measurements were carried out radial (instead of linear) for the first time. The results show possible inhomogeneities in the subgrade or in the bedding, which would not be recognized by the standard linear measurements. With the results from the already mentioned measurements, the remaining service life of the test tracks could be calculated.
6
Wang, Jinhua, Bing Wang, and Bin Wu. "Numerical Analysis of the Residual Heat Removal for the Spent Fuel Canister of HTR-PM in Fuel Loading Process." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30284.
Full textAbstract:
High Temperature Gas Cooled Reactor (HTGR) has inherent safety, and has been selected as one of the candidates for the Gen-IV nuclear energy system. In china, the project of the High Temperature Reactor Pebble bed Module (HTR-PM) is in design and construction process. Spherical fuel elements are chosen for the HTR-PM and the spent fuel elements will be stored in canister. The spent fuel canister will be delivered to wells for storage when fully loaded. The canister is covered by a steel cask for radiation shielding, and the cask is covered by a boron polyethylene sleeve to absorb neutrons from decay in fuel loading process. Normally, the residual heat is discharged by forced ventilation in fuel loading process. An auxiliary fan is set on top of the cask considering the possible mechanical failure for the operating fan. When losing normal power supply, the emergency power will be provided to the fans by the two line diesel generators respectively. In extreme conditions of mechanical failure for both fans, the residual heat could be discharged by natural ventilation. The temperature profiles of the different structures were studied in this paper with CFD method for both normal and accident conditions. The calculation results showed that, the maximum temperature of all of the structures are lower than the safety temperature limits in either normal or accident conditions; the temperature decreases rapidly with radial distance in the canister, and the maximum temperature is located at the center of the fuel pebble bed. So it is feasible to remove the residual heat of the spent fuel by natural ventilation in accident condition, and in the natural ventilation condition, the maximum temperature of the spent fuel, the canister shell, the shielding cask, and the boron polyethylene sleeve are lower than their safety temperature limits.
7
Dereziński, Michał, Rajiv Khanna, and Michael W. Mahoney. "Improved Guarantees and a Multiple-descent Curve for Column Subset Selection and the Nystrom Method (Extended Abstract)." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/647.
Full textAbstract:
The Column Subset Selection Problem (CSSP) and the Nystrom method are among the leading tools for constructing interpretable low-rank approximations of large datasets by selecting a small but representative set of features or instances. A fundamental question in this area is: what is the cost of this interpretability, i.e., how well can a data subset of size k compete with the best rank k approximation? We develop techniques which exploit spectral properties of the data matrix to obtain improved approximation guarantees which go beyond the standard worst-case analysis. Our approach leads to significantly better bounds for datasets with known rates of singular value decay, e.g., polynomial or exponential decay. Our analysis also reveals an intriguing phenomenon: the cost of interpretability as a function of k may exhibit multiple peaks and valleys, which we call a multiple-descent curve. A lower bound we establish shows that this behavior is not an artifact of our analysis, but rather it is an inherent property of the CSSP and Nystrom tasks. Finally, using the example of a radial basis function (RBF) kernel, we show that both our improved bounds and the multiple-descent curve can be observed on real datasets simply by varying the RBF parameter.
8
Fetterman, Robert J. "Advanced First Core Design for the Westinghouse AP1000." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75806.
Full textAbstract:
As the nuclear renaissance is now upon us and new plants are either under construction or being ordered, a considerable amount of attention has also turned to the design of the first fuel cycle. Requirements for core designs originate in the Utilities Requirements Document (URD) for the United States and the European Utilities Requirements (EUR) for Europe. First core designs created during the development of these documents were based on core design technology dating back to the 1970’s, where the first cycle core loading pattern placed the highest enrichment fuel on the core periphery and two other lower enrichments in the core interior. While this sort of core design provided acceptable performance, it underutilized the higher enriched fuel assemblies and tended to make transition to the first reload cycle challenging, especially considering that reload core designs are now almost entirely of the Low Leakage Loading Pattern (LLLP) design. The demands placed on today’s existing fleet of pressurized water reactors for improved fuel performance and economy are also desired for the upcoming Generation III+ fleet of plants. As a result of these demands, Westinghouse has developed an Advanced First Core (AFCPP) design for the initial cycle loading pattern. This loading pattern design simulates the reactivity distribution of an 18 month low leakage reload cycle design by placing the higher enriched assemblies in the core interior which results in improved uranium utilization for those fuel assemblies carried through the first and second reload cycles. Another feature of the advanced first core design is radial zoning of the high enriched assemblies, which allows these assemblies to be located in the core interior while still maintaining margin to peaking factor limits throughout the cycle. Finally, the advanced first core loading pattern also employs a variety of burnable absorber designs and lengths to yield radial and axial power distributions very similar to those found in typical low leakage reload cycle designs. This paper will describe each of these key features and demonstrate the operating margins of the AFC design and the ability of the AFC design to allow easy transition into 18 month low leakage reload cycles. The fuel economics of the AFC design will also be compared to those of a more traditional first core loading pattern.
9
Brownlie, Keith, and Biljana Rajlic. "Kingston Third Crossing." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0921.
Full textAbstract:
<p>Kingston Ontario is a city on the north eastern shore of Lake Ontario at the south end of the 202km long Rideau Canal, the oldest continually operated canal system in North America and a UNESCO World Heritage Site. The Cataraqui river forms the lower portion of the canal and separates central Kingston from its eastern suburbs.</p><p>The Third Crossing is a new 1.2km long multi-span two-lane highway bridge across the Cataraqui river, planned to increase east-west journey capacity and reduce congestion on existing routes and crossings. The project is intended to facilitate a significant increase in bike journeys, minimize maintenance liabilities and maximize service life.</p><p>The project is believed to be the first bridge in North America to adopt an Integrated Project Delivery (IPD) model, involving an alliance of the city, design and construction partners. The city’s Preliminary Design was radically revised through the IPD process to bridge a significant affordability gap. Strict funding deadlines required the re-design to be completed within the short period allocated for validation of the original design. The IPD model allowed that undertaking to progress efficiently and keep the project on track in challenging circumstances.</p><p>The revised design addresses complex environmental, stakeholder and heritage issues. A key requirement to acknowledge the World Heritage asset is addressed with a weathering steel arched bridge spanning 100m across the river’s boating channel to form a dynamic gateway to the canal.</p>
10
Williams, Matthew, and Wayne Walter. "Design, Build, and Test of a Permanently Implanted Prosthetic Hand." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33018.
Full textAbstract:
The feasibility of a permanently implanted prosthetic hand was evaluated from both an internal biocompatibility and exterior mechanics point of view. A literature review of the issues involved in permanent implantation of a percutanious device was performed in the areas of bone interaction and fixation and neural interface control. A theoretical implant was designed for a 90th percentile male, using a HA-G-Ti composite material to provide a permanent base to which the hand could attach. Using a radial implant length of 1.87 inches and an ulna implant length of 1.32 inches, the simulated implant could withstand a push out force of 10.260 pounds. Using nerve guidance channels and microelectrode arrays, a Regenerative Neural Interface was postulated to control the implant. The use of Laminin-5 was suggested as a method of preventing the lack of wound closure observed in percutanious devices. The exterior portion of a permanent artificial hand was analyzed by the construction of a robotic hand optimized for weight, size, grip force and wrist torque, power consumption and range of motion. Using a novel dual drive system, each finger was equipped with both joint position servos as well as a tendon. Fine grip shape was formed using the servos, while the tendon was pulled taunt when grasping an object. Control of the prosthetic hand was performed using a distributed network of micro-controllers. Each finger’s behavior was governed by a master/slave system where input from a control glove was processed by a master controller with joint servo and tendon instructions passed to lower-level controllers for management of hand actuators. The final weight of the prototype was 3.85 pounds and was approximately 25% larger than the 90th percentile male hand it was based on. Grip force was between 1.25 and 2 pounds per finger, depending on amount of finger flexion with a wrist lifting torque of 1.2 pounds at the center of the palm. The device had an average current draw of 3 amps in both normal operation and tight grasping. Range of motion was similar to that of the human model. Overall feasibility of the device is examined and factors involved in industrial implementation are discussed.